This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. Primary support for the subproject and the subproject's principal investigator may have been provided by other sources, including other NIH sources. The Total Cost listed for the subproject likely represents the estimated amount of Center infrastructure utilized by the subproject, not direct funding provided by the NCRR grant to the subproject or subproject staff. Causes of knee OA are unknown, but it is likely that biomechanical factors contribute to abnormal loading on the affected cartilage and bone. Effective non-surgical interventions are limited and may include strengthening, exercise and use of a cane or orthotic, but muscle activity may be the most significant modifiable factor. The proposed study is designed to investigate muscle forces and coordination strategies during gait in individuals with age-related osteoarthritis of the knee. This will be done thought a combination of MRI, gait analysis, electromyography, and biomechanical modeling and simulation. This project will build upon the clinical foundation projected by project #4, which takes a clinical approach to explore the progression of OA following TKA. Dr. Buchanan will serve as scientific mentor and Dr. Snyder-Mackler will be career mentor.